Methods for adjusting audio signals responsive to changes in a power supply level and related communications devices

Abstract

The generation of an audio output sound from an electronic communications device includes monitoring a level of an electrical power supply for the electrical communications device, and adjusting an audio input signal responsive to changes of the level of the electrical power supply for the electronic communications device. The adjusted audio input signal is amplified, and an output sound is generated responsive to the adjusted and amplified audio input signal. In addition, an audio output signal can be generated responsive to received sound including an echo of the output sound, an estimate of the echo of the output sound can be generated using the adjusted audio input signal and a model of an echo path of the output sound, and the echo portion of the audio output signal can be reduced using this estimate.

That which is claimed is:  
     
       1. A method of generating an audio output sound from an electronic communications device, said method comprising the steps of: 
       monitoring a level of an electrical power supply for the electrical communications device;  
       adjusting an audio input signal responsive to changes of the level of the electrical power supply for the electronic communications device;  
       after the adjusting step, amplifying the adjusted audio input signal; and  
       generating an output sound responsive to the adjusted and amplified audio input signal.  
     
     
       2. A method according to claim  1  further comprising the step of: 
       generating an audio output signal responsive to received sound including an echo of the output sound;  
       generating an estimate of the echo of the output sound using the adjusted audio input signal and a model of an echo path of the output sound; and  
       suppressing an echo portion of the audio output signal using the estimate of the echo of the output sound.  
     
     
       3. A method according to claim  1  wherein the adjusting step comprises adjusting a gain of the audio input signal so that the adjusted audio input signal does not exceed an amplitude that would result in clipping during the amplifying step at the monitored level of the electrical power supply. 
     
     
       4. A method according to claim  1  wherein the adjusting step comprises clipping portions of the audio input signal which exceed an amplitude that would result in clipping during the amplifying step at the monitored level of the electrical power supply. 
     
     
       5. A method according to claim  1  wherein the monitoring step comprises detecting a reduction in the level of the electrical power supply, and wherein the adjusting step comprises reducing a peak-to-peak swing of the audio input signal responsive to the detected reduction in the level of the electrical power supply. 
     
     
       6. A method according to claim  1  wherein the monitoring step comprises detecting an increase in the level of the electrical power supply, and wherein the adjusting step comprises increasing a peak-to-peak swing of the audio input signal responsive to the detected increase in the level of the electrical power supply. 
     
     
       7. A method according to claim  1  wherein the monitoring step comprises periodically sampling the level of the electrical power supply, storing a predetermined number of the sampled levels, and choosing the lowest of the stored samples to represent the level of the electrical power supply. 
     
     
       8. A method according to claim  1  wherein the monitoring step comprises scaling the level of the electrical power supply and filtering the scaled level to approximate negative peaks of the level of the electrical power supply. 
     
     
       9. A method according to claim  1  wherein the electrical power supply comprises a battery. 
     
     
       10. A method according to claim  9  wherein the battery comprises an automobile battery. 
     
     
       11. A method according to claim  1  wherein the step of adjusting the audio input signal comprises adjusting a digital audio input signal, wherein the amplifying step is preceded by the step of converting the digital adjusted audio input signal to an analog adjusted audio input signal, and wherein the amplifying step comprises amplifying the analog adjusted audio input signal. 
     
     
       12. A method of generating an audio output sound from an electronic communications device, said method comprising the steps of: 
       monitoring a level of an electrical power supply for the electrical communications device;  
       adjusting a digital audio input signal responsive to changes of the level of the electrical power supply for the electronic communications device;  
       converting the adjusted digital audio input signal to an adjusted analog audio input signal; and  
       generating an output sound responsive to the adjusted analog audio input signal.  
     
     
       13. A method according to claim  12  further comprising the step of: 
       generating an audio output signal responsive to received sound including an echo of the output sound;  
       generating an estimate of the echo of the output sound using the adjusted digital audio input signal and a model of an echo path of the output sound; and  
       suppressing an echo portion of the audio output signal using the estimate of the echo of the output sound.  
     
     
       14. A method according to claim  12  wherein the generating step is preceded by the step of: 
       amplifying the adjusted analog audio input signal.  
     
     
       15. A method according to claim  14  wherein the adjusting step comprises adjusting a gain of the digital audio input signal so that the adjusted digital audio input signal does not exceed an amplitude that would result in clipping during the amplifying step at the monitored level of the electrical power supply. 
     
     
       16. A method according to claim  14  wherein the adjusting step comprises clipping portions of the adjusted digital audio input signal which exceed an amplitude that would result in clipping during the amplifying step at the monitored level of the electrical power supply. 
     
     
       17. A method according to claim  12  wherein the monitoring step comprises detecting a reduction in the level of the electrical power supply, and wherein the adjusting step comprises reducing a peak-to-peak swing of the adjusted digital audio input signal responsive to the detected reduction in the level of the electrical power supply. 
     
     
       18. A method according to claim  12  wherein the monitoring step comprises detecting an increase in the level of the electrical power supply, and wherein the adjusting step comprises increasing a peak-to-peak swing of the adjusted digital audio input signal responsive to the detected increase in the level of the electrical power supply. 
     
     
       19. A method according to claim  12  wherein the monitoring step comprises periodically sampling the level of the electrical power supply, storing a predetermined number of the sampled levels, and choosing the lowest of the stored samples to represent the level of the electrical power supply. 
     
     
       20. A method according to claim  12  wherein the monitoring step comprises scaling the level of the electrical power supply and filtering the scaled level to approximate negative peaks of the level of the electrical power supply. 
     
     
       21. A method according to claim  12  wherein the electrical power supply comprises a battery. 
     
     
       22. A method according to claim  21  wherein the battery comprises an automobile battery. 
     
     
       23. An electronic communications device comprising: 
       a monitoring circuit that monitors a level of an electrical power supply for the electronic communications device;  
       an adjusting circuit coupled to the monitoring circuit that adjusts an audio input signal responsive to changes of the level of the power supply;  
       an amplifier coupled to the adjusting circuit that amplifies the adjusted audio input signal; and  
       an speaker coupled to the amplifier that generates an output sound responsive to the adjusted and amplified audio input signal.  
     
     
       24. An electronic communications device according to claim  23  further comprising: 
       a microphone that generates an audio output signal responsive to received sound including an echo of the output sound; and  
       an echo filter that generates an estimate of the echo of the output sound using the adjusted audio input signal and a model of an echo path of the output sound, and that suppresses an echo portion of the audio output signal using the estimate of the echo of the output sound.  
     
     
       25. An electronic communications device according to claim  23  wherein the adjusting circuit adjusts a gain of the audio input signal so that the adjusted audio input signal does not exceed an amplitude that would result in clipping during the amplifying step at the monitored level of the electrical power supply. 
     
     
       26. An electronic communications device according to claim  23  wherein the adjusting circuit clips portions of the audio input signal which exceed an amplitude that would result in clipping at the amplifier at the monitored level of the electrical power supply. 
     
     
       27. An electronic communications device according to claim  23  wherein the monitoring circuit detects a reduction in the level of the electrical power supply, and wherein the adjust circuit reduces a peak-to-peak swing of the audio input signal responsive to the detected reduction in the level of the electrical power supply. 
     
     
       28. An electronic communications device according to claim  23  wherein the monitoring circuit detects an increase in the level of the electrical power supply, and wherein the adjusting circuit increases a peak-to-peak swing of the audio input signal responsive to the detected increase in the level of the electrical power supply. 
     
     
       29. An electronic communications device according to claim  23  wherein the monitoring circuit periodically samples the level of the electrical power supply, storing a predetermined number of the sampled levels and choosing the lowest of the stored samples to represent the level of the electrical power supply. 
     
     
       30. An electronic communications device according to claim  23  wherein the monitoring circuit scales the level of the electrical power supply and filters the scaled level to approximate negative peaks of the level of the electrical power supply. 
     
     
       31. An electronic communications device according to claim  23  wherein the electrical power supply comprises a battery. 
     
     
       32. An electronic communications device according to claim  31  wherein the battery comprises an automobile battery. 
     
     
       33. An electronic communications device according to claim  23  wherein the adjusting circuit adjusts a digital audio input signal, the device further comprising: 
       a digital-to-analog converter between the adjusting circuit and the amplifier that converts the adjusted digital audio input signal to an adjusted analog audio input signal so that the amplifier amplifies the adjusted analog audio input signal.  
     
     
       34. An electronic communications device comprising: 
       a monitoring circuit that monitors a level of an electrical power supply for the electrical communications device;  
       an adjusting circuit coupled to the monitoring circuit that adjusts a digital audio input signal responsive to changes of the level of the electrical power supply for the electronic communications device;  
       a converter coupled to the adjusting circuit that converts the adjusted digital audio input signal to an adjusted analog audio input signal; and  
       a speaker coupled to the converter that generates an output sound responsive to the adjusted analog audio input signal.  
     
     
       35. An electronic communications device according to claim  34  further comprising: 
       a microphone that generates an audio output signal responsive to received sound including an echo of the output sound;  
       an echo filter that generates an estimate of the echo of the output sound using the adjusted digital audio input signal and a model of an echo path of the output sound and suppresses an echo portion of the audio output signal using the estimate of the echo of the output sound.  
     
     
       36. An electronic communications device according to claim  34  further comprising: 
       an amplifier coupled between the adjusting circuit and the speaker that amplifies the adjusted analog audio input signal.  
     
     
       37. An electronic communications device according to claim  36  wherein the adjusting circuit adjusts a gain of the digital audio input signal so that the adjusted digital audio input signal does not exceed an amplitude that would result in clipping at the amplifier at the monitored level of the electrical power supply. 
     
     
       38. An electronic communications device according to claim  36  wherein the adjusting circuit clips portions of the adjusted digital audio input signal which exceed an amplitude that would result in clipping during at the amplifier at the monitored level of the electrical power supply. 
     
     
       39. An electronic communications device according to claim  34  wherein the monitoring circuit detects a reduction in the level of the electrical power supply, and wherein the adjusting circuit reduces a peak-to-peak swing of the adjusted digital audio input signal responsive to the detected reduction in the level of the electrical power supply. 
     
     
       40. An electronic communications device according to claim  34  wherein the monitoring circuit detects an increase in the level of the electrical power supply, and wherein the adjusting circuit increases a peak-to-peak swing of the adjusted digital audio input signal responsive to the detected increase in the level of the electrical power supply. 
     
     
       41. An electronic communications device according to claim  34  wherein the monitoring circuit periodically samples the level of the electrical power supply, storing a predetermined number of the sampled levels and choosing the lowest of the stored samples to represent the level of the electrical power supply. 
     
     
       42. An electronic communications device according to claim  34  wherein the monitoring circuit scales the level of the electrical power supply and filters the scaled level to approximate negative peaks of the level of the electrical power supply. 
     
     
       43. An electronic communications device according to claim  34  wherein the electrical power supply comprises a battery. 
     
     
       44. An electronic communications device according to claim  43  wherein the battery comprises an automobile battery.